Online Sensorless Efficiency Estimation of Induction-Motor-Driven Pumps

According to published studies, about 22% of the industrial electricity is consumed by the centrifugal pumps driven by induction motors. The operating point of these systems are often far from the best efficiency point and so a large portion of energy is wasted resulting in economic loss. Therefore, estimating the efficiency of pumps without interrupting the normal system operation is of heigh importance. This paper present a non-intrusive approach toward estimating the efficiency of the whole motor-pump chain. The motor efficiency is calculated using only motor electrical signals along with the nameplate information. To estimate the pump efficiency, a hybrid method is adopted which uses the pump characteristic curve, impeller speed and affinity laws. Both estimation algorithms are based on electrical signature analysis (ESA) and electromechanical coupling which requires only motor terminal quantities i.e. current and voltage. The proposed methods are tested on laboratory setups and the experimental results show their effectiveness in estimating the efficiency of induction-motor-driven pumps.